﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Bai24_C_Sharp
{
    abstract class absClass
    {
        public int Add(int x, int y)
        {
            return x + y;
        }
        public abstract int Mul(int x, int y);
    }
    class absDerived : absClass
    {
        public override int Mul(int x, int y)
        {
            return x * y;
        }

    }
}
